BIOBUTANOL

AS AN

ALTERNATE FUEL

Assignment 1

Submitted by:Rahul Sharma(08109045)

Tarun Kumar(08109062)

Rahul Sharma(08110014)

Ankur Kejriwal(08113007)

1

INTRODUCTION

•Earlier bioethanol is mainly used as alternative fuel

•But now days biobutanol is replacing bioethanol due to

its various advantages over it:-

It is non-hygroscopic in nature

Doesn’t cause corrosion

It has more calorific value than ethanol

•Biobutanol is basically a alcohal with four carbon atom

•Also sometimes called biogasoline.

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HOW IT IS PREPARED

• Biobutanol can be produce by both petrochemical and

fermentative process but it is mainly produced by

fermentation of biomass by the A.B.E. process

• The feedstocks are the same as for ethanol: energy crops

such as sugar beets, sugar cane, corn grain, wheat and

cassava

• Microbes, specifically of the Clostridium

acetobutylicum, are introduced to the sugars produced

from the biomass.

3

FERMENTATION

• The Butanol fermentation process feeds fundamentally has

similar process as an ethanol process

• Butanol fermentation, also referred to as alcoholic

fermentation, is a biological process in which sugars such

as glucose, fructose, and sucrose are converted into cellular

energy.

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REACTIONS INVOLVED

• C12H22O11 +H2O + invertase →2 C6H12O6

• C6H12O6 + Zymase → C4H9OH + 2CO2 + H2O

• Before fermentation takes place, one glucose molecule

is broken down into two pyruvate molecules. This is

known as glycolysis

• Glycolysis is summarized by the chemical equation

• C6H12O6 + 2 ADP + 2 Pi + 2 NAD+ →

2CH3COCOO− + 2 ATP + 2 NADH + 2 H2O + 2H+

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PROPERTIES

• Octane rating: The octane rating of n-butanol is similar to that of

gasoline but lower than that of ethanol and methanol.

n-Butanol has a RON (Research Octane number) of 96 and a MON (Motor

octane number) of 78

• Air-fuel ratio:Alcohol fuels are partially oxidized and therefore need to

run at richer mixtures than gasoline

• Specific energy:The net energy released per cycle is higher for butanol

than ethanol or methanol and about 10% higher than for gasoline

• Viscosity: The kinematic viscosity of butanol is several times higher

than that of gasoline and about as viscous as high quality diesel fuel

• Heat of vaporization: Heat of vaporization of butanol is less than half

of that of ethanol.

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COMPARISION WITH OTHER FUELS

Fuel Energy

density

MJ/L

Air-fuel

ratio

Specifi

c

energy

MJ/KG

air

Heat of

vaporiz

ation

MJ/KG

RON MON

Gasoline 32 15 2.9 0.36 95 90

Ethanol 19.6 9 3 0.92 107 89

Methanol 16 7 3.1 1.2 106 92

Bio-

Butanol

30 12 3.2 0.43 96 78

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ADVANTAGES

• Reduces carbon emission

• Higher octane no. than gasoline

• Vehicles require less or no modification to use it

• Biobutanol is good for global farmers

• Can be easily added to conventional gasoline, due

to its low vapour pressure

• It is less corrosive than ethanol.8

DISADVANTAGES

• Butanol is toxic at a rate of 20g per liter

• Biodiversity – A large amount of arable land is required to

grow crops. This could see some natural habitats destroyed

including rainforests

•Alcohol based fuel are not compatible with some fuel

system component.

9

APPLICATION

•As a solvent in paint-and-varnish industry

• In the production of resins and plastifiers

•As in the synthesis of multiple organic compounds

• Used as a component of traditional fuels or individually as

a fuel for transportation vehicles.

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BIOBUTANOL

AS AN

ALTERNATE FUEL

Assignment 2

Submitted by:Rahul Sharma(08109045)

Tarun Kumar(08109062)

Rahul Sharma(08110014)

Ankur Kejriwal(08113007)

11

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CONTENTS

• Determination of stoichiometric Air-Fuel ratio

• Modification in IC engine along with comparing it with

gasoline.

• Variation with specific heat

• Effect on performance

DETERMINATION OF

STOICHIOMETRIC AIR-FUEL RATIO

• C4H9OH (Bio Butanol)-Molar Mass is equal to 74 units

• O2 (Oxygen)-Molar Mass is equal to 32 units

• Molar Mass of Carbon in Bio Butanol is equal to 48 units

• Molar Mass of Oxygen in Bio Butanol is equal to 16 units

C4H9OH + 6O2 → 4CO2 +5H2O - - - - ---(i)

4C + 4O2 → 4CO2 - - - - ---(ii)

5H2 + 5/2O2 → 5H2O - - - - ---(iii)

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Consider 74 kg of fuel(Bio Butanol)

• In 74 kg of bio- butanol, amount of carbon is 48 kg

• By reaction (ii) we can see for combustion of 48 kg of carbon

128kg of oxygen is needed

• By reaction (iii),we can see for 10 kg of hydrogen ,80 kg oxygen is

needed

• 16 kg of oxygen is already present in 74 kg of fuel

Therefore amount of total oxygen needed for complete combustion of

fuel is (80+128-16) is equal to 192 kg

• Now according to the gravemetric analysis oxygen present in air at

STP is 23%

Therefore for 192 kg of oxygen, air required is equal to 834.78 kg

For 74 kg of fuel → 834.78 kg of air

For 1 kg of fuel → 11.28 kg of air

Therefore Air-Fuel ratio → 11.28

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CALCULATIONS

48 kg of Carbon required → 128 kg of O2 required

1 kg of Carbon required → 128/48 kg of O2 required

10 kg of hydrogen required → 80 kg of O2 required

1 kg of hydrogen required → 8 kg of O2 required

Total amount of Oxygen = 5/2*32+4*32-16

=192 kg of O2 required

Amount of O2 required at STP = 192*100/23

=834.748

Thus 74 kg of fuel → 834.78

1 kg of fuel → 834.78/74 =11.28

Therefore stoichiometric Air-Fuel ratio is 11.28

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MODIFICATION IN GASOLINE

ENGINE

Based on stoichiometric air fuel ratio

• Stoichiometric air fuel ratio of Bio-Butanol :- 11.28

• Stoichiometric air fuel ratio of Gasoline :- 14.7

Conclusion : Less amount of air is required per kg of

fuel burnt

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• Changes in intake and exhaust manifold

(a) Decrease the diameter of intake and exhaust manifold and inlet valve

(b) Increment in length of intake manifold

MODIFICATIONS

• Size of turbocharger or supercharger(if installed) could be reduced

• Changes in carburetor

(a) Increase the diameter of main fuel metering and idling nozzles

(b)Increase the level of fuel in the float chamber

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Based on Flash Point and Ignition temperature

• Flash Point of Bio-Butanol :- 95 °F

• Flash Point of Gasoline :- -45°F

• Ignition temperature of gasoline = 300°C

• Ignition temperature of bio butanol = 343°C

• A higher flash point and ignition temperature makes biobutanol much

safer and less explosive

• Requires higher temperature to explode

Conclusion:

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MODIFICATIONS

• Spark plug needed should be able to synchronize with higher ignition

temperature and higher flash point

• No need to modify fuel tank safety system

•A pre heater of air fuel mixture may be required to heat the air fuel

mixture to the flash point

•A pre heater is a device which is used to raise the temperature of air

fuel mixture before sending it to the combustion chamber

• Instead of using external energy consumption device, heat of exhaust

gas can be used to raise the temperature of air fuel mixture

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Based on energy content

• Energy content of Bio-Butanol : 30 MJ/L

• Energy content of Gasoline : 32 MJ/L

Conclusion : One liter of bio butanol will give slightly lesser

amount of energy than 1 liter of gasoline

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MODIFICATIONS

• No need to increase the size of fuel tank as heat content of both the fuel is

almost same

• No considerable variation on mileage of the vehicle on replacing the fuel

• Indicated power will be decreased by a small negligible amount

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Based on Density

0.73

0.74

0.75

0.76

0.77

0.78

0.79

0.8

0.81

0.82

0.83

0 10 20 30 40 50 60

Scale: X-axis- temperature (°C)

Y-axis- Density (gm/cm3)

Yellow line- gasoline and brown line-

biobutanol

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MODIFICATIONS

• Due to lesser density atomization of fuel in the combustion chamber will

be easier. So homogeneity of air fuel ratio will increase

• Ignition lag will be minimized in case of liquid fuel injection

So ignition delay can be reduced

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2.1

2.2

2.3

2.4

2.5

2.6

2.7

100 120 140 160 180 200

220

Scale :-

X-axis= temperature(°C)

Y-axis= specific heat( KJ/kg-°C)

VARIATION OF SPECIFIC HEAT

EFFECT ON PERFORMANCE

• Reduction in knocking, hence increase in engine life

• Lesser power output

• Lesser efficiency at high speed

• Lower toxic level in emission

• Better performance at high altitude

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REFERENCES

• www.wikipedia.org

• IC engine book by V GANESHAN

• Journal published by Avinash kumar Aggarwal

• Bionomicfuel.com